1. Field of the Invention
The invention relates to a sealing arrangement, in particular for a metering piston of a pneumatic valve, including a sealing ring which is made at least in part of an elastic material and which exhibits an essentially discoid, outer sealing region with a sealing edge that rests in an installed state against the surface region to be sealed, and a holding region which is arranged under partial pretension in a corresponding groove-shaped recess of the metering piston.
2. The Prior Art
There exist for various uses devices, for example, pneumatic valves, whose metering pistons are sealed with elastic seals. These seals can be mounted either on the metering piston itself or on the housing and, thus, also move either with each motion of the metering piston or remain stationary in the installation position in the housing. Especially for sealing arrangements of the aforementioned kind where the sealing ring is mounted on the metering piston, there exist sealing rings which lie like O-rings in corresponding grooves of the metering piston. At the same time there exist various shapes for the cross section of the sealing rings, whereby, however, substantially discoid sealing rings are preferably used.
These sealing arrangements have in particular the drawback that an air current flowing by, as is always the case in switching valves, can pull out the sealing ring, an event which one strives to prevent frequently by means of a sliding ring, pulled externally over the sealing ring, or a special operating edge construction, a solution that is associated, however, with a more complicated and, thus, more expensive construction.
Through modification of the aforementioned washer seals there also exist sealing arrangements where the sealing ring is not simply embedded in grooves of the metering piston, but rather where the piston is assembled from individual parts with sealing rings lying in between and a connecting piece at the same time that the sealing arrangement or the sealing ring is assembled, whereby radially oriented seams at the axial surfaces of the sealing rings are inserted into the corresponding grooves of the spacers. This holding at the seams in the vicinity of the sealing diameter does prevent the sealing ring from being pulled out of the groove, as described above, but simultaneously the construction of the piston and thus the assembly becomes more complicated due to the necessary division.